Conventionally, the stereo shape of the ocular fundus must be viewed in order to diagnose glaucoma. Stereo photographs, i.e., two (a plurality of) images that have a parallax with respect to the same subject-eye, are taken and displayed in pairs to thereby view the subject's eye stereographically.
A fundus camera that can take an image having a parallax is provided with a photographic stop (two-aperture stop) having two left and right stops (apertures) that is positioned in conjugate with the anterior ocular segment of the subject's eye (in conjugate with the pupil) relative to the objective lens, and a beam of light that has passed through each of the apertures from the ocular fundus is received as left and right images on the film surface or on the image surface of an imaging device to obtain an image for stereoscopic viewing.
With such a fundus camera, photography from one aperture of a photographic stop is switched to photography from the other aperture in accordance with the operation of a shutter to acquire two left and right images in succession (Patent Document 1). Alternatively, a first image is taken with a single shot, a second image is then acquired in a sequential manner, and the images are alternately displayed on a monitor (patent Document 2).
Also known are a fundus camera (Patent Document 3) that is provided with a photographic stop having an ordinary aperture stop and a two-aperture stop for stereographic photography, in which the ordinary aperture stop is enabled during observation to carry out observations, and the two-aperture stop is enabled during stereographic photography to carry out photography; a fundus camera for stereoscopic viewing (Patent Document 4) wherein the spacing of two apertures for bisecting a beam of light that has passed through an objective lens is varied in accordance with the pupil diameter; a fundus camera (Patent Document 5) in which a ring slit that restricts illumination light and a two-aperture stop (photographic stop) are switched in conjunction for two use for binocular photography and monocular photography; and a fundus camera (Patent Document 6) in which the ring slit and the stop can be switched simultaneously in accordance with the photographic magnification during photography.
Also known is a configuration in which photographic condition information such as information of the photographed left and right eyes are recorded and stored in association with the photographic image (Patent Document 7), or in which the position of a fixation lamp is sequentially varied, the ocular fundus is stereographically or panoramically photographed from various angles, and the images are recorded in association with the position of the fixation lamp (Patent Document 8).
Also known is a fundus camera (Patent Document 9) in which the image of the ocular fundus is temporarily stored in high-speed memory, and the recorded image of the ocular fundus is transferred to an external low-speed recording apparatus at a transfer timing that corresponds to the photography mode, thereby making continuous photography of the ocular fundus possible.
Patent Document 1: JP-A 1984-90547
Patent Document 2: JP-A 1998-75932
Patent Document 3: JP-A 1984-164033
Patent Document 4: JP-A 1990-5922
Patent Document 5: JP-A 1993-245109
Patent Document 6: JP-A 1993-305059
Patent Document 7: JP-A 2002-17681
Patent Document 8: JP-A 2004-135941
Patent Document 9: JP-A 2004-97648